Rev. 1.10

9

July 01, 2011

HT16K23

Standby Mode

In the standby mode, the HT16K23 cannot accept any input command or write data to the display RAM except for

the system set command.

If standby mode is selected with the “S” bit of system set command is set to “0”, the status of the standby mode is

as follows:

● System Oscillator is off.

● LCD display is off.

● Key scan stopped.

● All key data and INT flags are cleared, until the standby mode is cancelled.

● The key matrix is pushed by any key or if the “S” bit of the system set command is set to “1”, this standby

mode will be cancelled and the device will wake-up.

● All common pins are set to VSS.

● If the “INT/ROW” bit of mode set command is set to “0”, all segment pins are changed to input pins.

● If the “INT/ROW” bit of mode set command is set to “1”: all segment pins are changed to input pins except for

the INT pin (output).

● The INT pin output keeps a high level when the “ACT” bit of the mode set command is set to “0”,.The INT pin

output keeps to a low level when the “ACT” bit of the mode set command is set to “1”, if the “INT/ROW” bit

of mode set command is set to “1”.

Wake-up

● Wake-up is implemented by a key press by any key or if the “S” bit of the system set command is set to “1”.

Then a key scan is performed.

● System Oscillator restarts for normal operation.

● The previous output will be displayed until updated by each mode command set.

● The relationship between Wake-up and any key press delay timeless and INT output and INT flag status is as

follows:

Wake-up

Standby mode command

set from MCU

Read key data command

set from MCU

INT flag or INT pin output

Any key

Press

Release key

2 frame cycle

Normal active status

HT16K23 operation status

Standby status

Press

2 frame cycle

< 2 frame cycle

Release key

Normal active status

Press

Release

(When the act bit is set to “1”)

Key data are updated

Key data are updated

When after the key data has been

read,Clears the key data RAM.

When after the key data has been

read,Clears the key data RAM.